Method of treating steel.



UNITED STATES PATENT OFFICE.

AUGUSTE J. ROSSI, OF NIAGARA FALLS, NEW YORK, ASSIGNOR TO THE TITANIUM ALLOY MANUFACTURING COMPANY, OF NEW YORK, N. Y., A CORPORATION OF Patented Jan. 13, 1914.

MAINE.

METHOD OF TREATING STEEL.

1,084,036. Specification of Letters Patent.

No Drawing.

Application filed May 3, 1912. Serial No. 694,915.

To all whom it may concern:

Be it known that I, AUGUSTE J. Rossi, a citizen of the United States, and a resident of Niagara Falls, in the county of Niagara and State of New York have invented a certain new and useful Method of Treating Steel, of which the following is a specification.

The objects of my present invention comprise the imparting to steel, particularly rails employed in railroad construction as the bearing surface for locomotives, motors and rolling stock, not only greater hardness than heretofore, but also at the same time greater endurance and greater capacity to resist shock and vibrations, and I attain these objects by the methods of treatment hereinafter described. For. example, tinpresent re uirements specified as 1ndispen-.

sable in rai s ofthe type referred to embrace the greatest possible hardness or capacity to resist frictional wear, and not only this but the greatest possible endurance so called, being the capacity to endure, without undue disintegration, repeated momenta shocks under high pressures in various dlI'GCtlOIlS,

and also the capacity to resist the disintegrating effects imparted by vibration. Hitherto it has been well understood that hardness. is imparted to such rails substantially proportionately to their content of carbon, but the desired increase of said content has proved impossible beyond certain comparatively low limits even by resort to addition of certain percentages of manganese, say about 1% or less, notwithstanding which additions, or even greater additions, of manganese, it has nevertheless still proved impossible, in practice, to incorporate more than say 0.5% to 0.6%of carbon Without imparting prohibitory brittleness.

The presence of the manganese, up to -a oer-f tain point, appears to overcome the brittlenes's imparte the carbon to the extent of permitting the rail to be rolled successfully.

and, without the said addition of manganese in sufiicient amount, rail material containing as high as the aforesaid 0.5% and 0.6% of carbon has proved impossible to be rolled. It appears however to be understood at present that said use of manganese imparts to the product some undesirable qualities, as for instance probably retention therein of sulfid of manganese, to which has been attributed evil efi'ects. Moreover, as above implied, the employment of manganese for th s specific purpose is limited manganese bem unable to counteract sufficiently the britt eness imparted by the carbon in higher than the above stated percentages. My researches have demonstrated that by thepres ence of titanium in lieu of manganese for the specific purpose for which the latter has been employed as aforesaid, not only is the brittleness attributable to, I may say, unlimited increase of carbon perfectly controllable, it being thus possible to dispense entirely with manganese for the purpose stated, but also that the titanium, in proper amounts, is capable of imparting to the resulting rail having substantially any desired content of carbon, not only increased elastic hithertounderstood to result from purifymg action of titanium, but also and particularly, as I have recently demonstrated, certain additional properties and characteristics satisfying the present requirements in rails as above stated, towit, unprecedented hardness and also endurance and capacity to resist vibration. tioned characteristics of the rail embodying titanium to bev due in part to the combined presence therein of the said high percentages of carbon and a sufficient amount of titanium to overcome the brittleness imparted by such carbon contents. At all events it will be understood that the superior capacity of the rail to resist successfully attrition is due in part to the presence of the high percentage ofcarbon admissible by my treatment, whereas, on the other hand, this characteristic would, however desirable, prove impracticable, for rollin and otherav'ise, without the presence of tie titanium, that is to say its novel effect when coacting with novel percentages of carbon upon the structure of the steel as for instance the groupings of its ferrite, pearlite and cement ite, which results in overcoming its otherwise prohibitory brittleness and imparting thereto, in addition to hardness, the em durance and resistance to vibration re--' ferred to.

It will be understood that my present invention comprises .not only the improvement of steel, generally speaking, by adding thereto While molten a quantity of titanium suflicient to chemically combine with undesired elements "and compounds present and thus insure a resulting product free from such impurities comprising slags and oontaining also substantially no, or traces only of, titanium whereby certain highly desirable characteristics are imparted due to the complete purification of thewmetal, such being increased elastic limit, elongation and ultimate strength. On the contrary my present invention comprises not only the improvement of the metal by purification referred to, but also, and particularly, in addition to this, the imparting to steel rails for example of qualities unattainable by the said purification merely, and the accomplishment of this novel result by means of increasing the carbon content of said rails to any degree desired above that hitherto practicable, and by additions of titanium not only suflicient to purify the metal as" aforesaid but also to insure retention in the final product of an amount of titanium suf- -ficient, in combination with said carbon, to

impart the increased hardness and also the increased endurance and resistance to vibration which it is my object to secure.

My present invention is practised as follows To the molten steel from which the rails are to be ultimately rolled, said steel containing the desired high percentage of carbon. which may be as high as 0.85% or as much higher as required, I add a relatively small quantity of metallic titanium, preferably in the form of the alloy of that metal with iron known as ferro-titanium, which may be produced for instance as per Letters Patent No. 609,466, granted to me August 23, 1898. The said amount of titanium is proportioned to satisfy the chemical afiinities of previously ascertained undesired elements and compounds contained in or absorbed by the steel and thus secure their removal including slags by the process for which Letters Patent No. 1,003,805, were granted to me on September 19, 1911. In this instance however I also intentionally add to the said amount of titanium so ascertained enough additional titanium to insure the retention in the final product, after the titanium has performed its aforesaid purifying function, of a certain amount of that metal being enough to im art to the final product such endurance an resistance to vibration as is required to overcome completely the otherwise prohibitory' brittleness to be expected from the presence of the particular content of carbon employed. Anything in excess of the amount of titanium thus specified will prove not only a waste of the metal for the particular pu ose in.

hand, but also, in some cases, possib y deleterious as imparting characteristics and qualities as yet undetermined. and which are.

likely to prove of decided disadvantage in steel rails. .It will be apparent that the aggregate amount of titamum thus added .solves therein promptly and to'the steel as aforesaid will depend upon theparticular requirements of each case as determined not only b knowledge of the character and extent 0 the impurities contained in the steel but also upon the crcentage of carbon employed, and furt ermore upon tests of specimens of each type of steel treated to determine the amount of titanium required in the final product to insure, notwithstanding the high carbon content, absence of brittleness and such endurance and resistance to vibration as may be required.

Iprefer to introduce the titanium in the form of its alloy with a ferro-metal as aforesaid, the said alloy containin from 10 to 12% or thereabout of meta ic titanium. In some instances I have found that as little as one-third of 1% of the ,said alloy last mentioned is sufficient to insure by its chemical combination with undesired elements and compounds entire removal of the latter including slags, and that in such instances in which the steel treated contained as high as 0.85% of carbon the further addition of from 5 of 1% to 1%% of the said alloy has proved sufiicient to overcome all brittleness attributable to said 0.85% carbon and also to impart to the re: sulting rails qualities of endurance and resistance to vibration hitherto I believe unattained and otherwise unattainable. For example in one instance in which the carbon content of the steel was 0.85% I addeda perfectly, and under the vibration test with stood over sixty million vibrations'without impairment; also on the breaking test the said rails proved' very superior under the severest strains, for instance between supports five feet apart endurin several central impacts of a-ton weight ailing thereon 14 to 16 feet, whereas the. tests for hardness disclosed-that the surfaces of said rails were from 200 to 300 per cent. harder than the previously best approved so -called hard carbon rails analyzing at 0.50% to 0.60% carbon, 0.85% manganese and 0.10% silicon.

I refrain from specifying more fully the method of adding the ferro-titanium to the steel bath as this is already well understood in the art. The bath being maintained at the melting point of steel, the titanium so introduced in alloy with/ferro metal disperforms. its functions on the metal and its impurities as aforesaid. Recent microscopic, and other tests have demonstrated that the efiect of the residual titanium introduced as per my present invention as aforesaid is-a parently to change in important and bene cial par ticulars the structure of the steel as regards roe-ante than 1%.

l Vhile the beneficial result of my novel method appears attributable to the combined eifect of a high percentage of carbon with a small percentage of titanium in the resultingproduct, ll may also in some cases employ with said high percentages of carbon and low percentages of titanium characterizing my present invention a small amount of manganese, but very much less than formerly required to overcome brittleness imparted by a much lower than 0.50% carbon content. For example in some instances l have thus added manganese so as to have in the final rail product not to exceed 0.60% to 0.18% of manganese. Tn fact in some special types of steel the presence of a thus minute content of manganese, as compared with that formerly used and indispensable, is of advantage for special purposes, or to satisfy special requirementsother than actual prevention of carbon-imparted brittleness.

l am aware that heretofore titanium, either by itself, or, more usually, in combination with other elements hostile to my present purpose, has been retained in final steel products for the purpose of producing what are now well known in the art as alloyed steels, i. c. steels which owe their distinguishing properties chiefly to the presence of a thereto added and therein retained element, or elements, other than carbon. But on the contrary, a distinguishing feature of my present invention is the augmentation of the carbon content, in steel, beyond what previously deemed practically by aid of manganese and this for the purpose ofimparting to the final product, in roportionally higher degree than hereto ore, distinguishing properties due to presence of high percentages of carbon, my addition and retention of titanium in such product though containing, for other purposes, much less manganese than sufficient to overcome brittleness, being in aid of such augmentation of carbon, and for the specific purpose of overcoming the hitherto prohibitory brittleness thereby imparted notwithstanding any content of manganese, and such retention of titanium bein sufiicient in amount to accomplish my sai purpose, but insuficient to justify designation of the product as a titanium alloyed steel, the resulting product being also characterized as being steel unassociated with metals other than titanium and manganese.

What I claim as new and desire to secure by Letters Patent is the following, viz

1. The method of treating steel which consists in incorporating carbon in quantity suflicient to produce any desired degree of hardness and to the molten product adding titanium and manganese in quantity Suficient to prevent any undesired brittleness in the resulting steel product characterized as containing titanium and manganese and as unalloyed with other metals, substantially as described.

2. The method of treating steel which consists in incorporating carbon 7 in quantity sufiicient to produce any desired degree of hardness and to the molten product adding titanium and manganese in quantity sufiicient to prevent any undesired brittleness-in the resulting steel product characterized as containing manganese, titanium less than 0.50 per cent, and as unalloyed with other metals, substantially as described.

3. The method of treating steel which consists in incorporating carbon in quantity sufficient to produce any desired degree of hardness and to the molten product adding titanium and manganese in quantity sufficient to prevent any undesired brittleness in the resulting steel product characterized as containing titanium, manganese less than 0.60 per cent, and as unalloyed with other metals.

AUGUSTEJ. RUSST. Witnesses:

WILLIAM F. MEREDITH, ANDREW Tnorrrson. 

